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Comparison of Reverse-Transcription Polymerase Chain Reaction Cycle Threshold Values From Respiratory Specimens in
John Strutner1, Nanda Ramchandar2, Shruti Dubey3
1Department of Pediatrics, University of California, San Diego, San Diego, California, USA.
Insights
Symptomatic children and those under 5 years old infected with SARS-CoV-2 may have higher viral loads. This study compared viral load indicators in symptomatic versus asymptomatic children with COVID-19.
Area of Science:
- Pediatric infectious diseases
- Virology
- Epidemiology
Background:
- Understanding severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) viral kinetics is crucial for managing transmission, treatment, and protective measures.
- The transmission potential of asymptomatic infected children requires further investigation.
- This study aimed to compare viral load indicators between symptomatic and asymptomatic children with SARS-CoV-2.
Purpose of the Study:
- To determine if asymptomatic children infected with SARS-CoV-2 exhibit different viral loads compared to symptomatic children.
- To analyze the impact of age on viral load in pediatric SARS-CoV-2 infections.
Main Methods:
- A retrospective cross-sectional study was conducted.
- PCR cycle threshold (Ct) values from respiratory samples of 728 children who tested positive for SARS-CoV-2 were analyzed.
- Data were collected over a 4-month period at a tertiary care children's hospital.
Main Results:
- Symptomatic children (71.2% of the cohort) had a significantly lower mean Ct value (19.9) compared to asymptomatic children (23.5), indicating higher viral load.
- The mean PCR Ct value was lowest in children younger than 5 years of age.
- A statistically significant difference was observed between symptomatic and asymptomatic groups (P < .001).
Conclusions:
- Symptomatic children and younger children (<5 years) infected with SARS-CoV-2 may exhibit higher nasopharyngeal viral loads than asymptomatic children.
- These findings suggest potential differences in transmission dynamics based on symptom status and age.
- Further research is necessary to fully assess the transmission potential from asymptomatic pediatric cases.
Background:
Understanding viral kinetics of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is important to assess risk of transmission, manage treatment, and determine the need for isolation and protective equipment. The impact of viral load in asymptomatic infected children is important to understand transmission potential. We sought to determine whether children deemed to be asymptomatic had a difference in the polymerase chain reaction (PCR) cycle threshold (Ct) value of respiratory samples from symptomatic children with SARS-CoV-2 infection.
Methods:
This was a retrospective cross-sectional study to compare PCR Ct values of children who tested positive for SARS-CoV-2 by respiratory samples collected over a 4-month period at a large tertiary care children's hospital.
Results:
We analyzed 728 children who tested positive for SARS-CoV-2 by reverse-transcription PCR (RT-PCR) from a respiratory sample over a 4-month period and for whom data were available in the electronic medical record. Overall, 71.2% of infected children were symptomatic. The mean Ct value for symptomatic patients (Ct mean, 19.9 [standard deviation, 6.3]) was significantly lower than for asymptomatic patients (Ct mean, 23.5 [standard deviation, 6.9]) (P < .001; 95% confidence interval, 2.6-4.6). The mean PCR Ct value was lowest in children <5 years of age.
Conclusions:
In this retrospective review of children who tested positive by RT-PCR for SARS-CoV-2, the mean Ct was significantly lower in symptomatic children and was lowest in children <5 years of age, indicating that symptomatic children and younger children infected with SARS-CoV-2 may have a higher viral load in the nasopharynx compared to asymptomatic children. Further studies are needed to assess the transmission potential from asymptomatic children.
